Derailleur

ABSTRACT

A derailleur comprises a base member, a movable member, a link member, and a biasing mechanism. The movable member is configured to be movable with respect to the base member between a retracted position and an extended position. The link member is configured to movably couple the movable member to the base member. The biasing mechanism is configured to bias the link member such that the movable member is disposed at one of the retracted position and the extended position. The biasing mechanism comprises a biasing member and an intermediate member. The biasing member has a first end portion. The intermediate member is separately provided from the movable member and the link member so as to transmit biasing force of the biasing member from the first end portion to one of the movable member and the link member through the intermediate member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a derailleur.

2. Discussion of the Background

Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. One component that has been recently redesigned is a derailleur. The derailleur laterally shifts a bicycle chain to change gears of the bicycle. A front derailleur and a rear derailleur are known as the derailleur.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the present invention, a derailleur comprises a base member, a movable member, a link member, and a biasing mechanism. The base member is configured to be attached to a bicycle frame. The movable member is configured to be movable with respect to the base member between a retracted position and an extended position at which the movable member is farther from the base member than the retracted position. The link member is configured to movably couple the movable member to the base member. The biasing mechanism is configured to bias the link member such that the movable member is disposed at one of the retracted position and the extended position. The biasing mechanism comprises a biasing member and an intermediate member. The biasing member has a first end portion. The intermediate member is separately provided from the movable member and the link member so as to transmit biasing force of the biasing member from the first end portion to one of the movable member and the link member through the intermediate member.

In accordance with a second aspect of the present invention, the derailleur according to the first aspect is configured so that the intermediate member is configured to transmit the biasing force of the biasing member from the first end portion to the link member.

In accordance with a third aspect of the present invention, the derailleur according to the first aspect is configured so that the biasing mechanism is configured to bias the link member such that the movable member is disposed at the retracted position.

In accordance with a fourth aspect of the present invention, the derailleur according to the first aspect is configured so that the intermediate member includes a first part and a second part. The first part is configured to engage with the first end portion of the biasing member. The second part is configured to engage with the one of the link member and the movable member and is configured to be detachably attached to the first part.

In accordance with a fifth aspect of the present invention, the derailleur according to the fourth aspect is configured so that the biasing member comprises a torsion spring including a cylindrical part from which the first end portion extends. The first part includes an inside portion and an outside portion. The inside portion is configured to be provided inside the cylindrical part. The outside portion is configured to be provided outside the cylindrical part. The second part is configured to be detachably attached to the outside portion.

In accordance with a sixth aspect of the present invention, the derailleur according to the fifth aspect is configured so that the movable member is pivotally connected to the link member via a rotational axle. The cylindrical part of the biasing member and the intermediate member are arranged on the rotational axle.

In accordance with a seventh aspect of the present invention, the derailleur according to the sixth aspect is configured so that the outside portion is configured to engage with the first end portion of the biasing member.

In accordance with an eighth aspect of the present invention, the derailleur according to the seventh aspect is configured so that the inside portion has a first outer diameter. The outside portion has a second outer diameter which is larger than the first outer diameter.

In accordance with a ninth aspect of the present invention, the derailleur according to the sixth aspect is configured so that the outside portion is provided between the biasing member and the link member in an axial direction of the rotational axle.

In accordance with a tenth aspect of the present invention, the derailleur according to the fifth aspect is configured so that the outside portion includes a tool engagement portion with which a tool is to engage when the derailleur is assembled.

In accordance with an eleventh aspect of the present invention, the derailleur according to the tenth aspect is configured so that the tool engagement portion comprises at least one tool engaging opening with which the tool is to engage when the derailleur is assembled.

In accordance with a twelfth aspect of the present invention, the derailleur according to the tenth aspect is configured so that the tool engagement portion comprises a plurality of tool engaging openings with which the tool is to engage when the derailleur is assembled.

In accordance with a thirteenth aspect of the present invention, the derailleur according to the tenth aspect is configured so that the outside portion further includes a pin engaging opening. The second part comprises a pin configured to engage with the pin engaging opening.

In accordance with a fourteenth aspect of the present invention, the derailleur according to the fourth aspect is configured so that the intermediate member is configured to transmit the biasing force of the biasing member from the first end portion to the link member. The link member includes a recessed portion configured to engage with the second part.

In accordance with a fifteenth aspect of the present invention, the derailleur according to the first aspect is configured so that the link member includes a proximal end portion pivotally connected to the base member and a distal end portion pivotally connected to the movable member. The link member is configured such that the distal end portion moves in a forward-rearward direction of the bicycle frame when the movable member moves between the retracted position and the extended position.

In accordance with a sixteenth aspect of the present invention, the derailleur according to the first aspect further comprises an additional link member configured to couple the movable member to the base member such that the movable member is movable with respect to the base member between the retracted position and the extended position. The base member, the movable member, the link member, and the additional link member define a four-bar linkage.

In accordance with a seventeenth aspect of the present invention, the derailleur according to the first aspect is configured so that the intermediate member is provided on a first side of the movable member. The first side is opposite to a second side of the movable member and is closer to the bicycle frame than the second side in a state where the base member is attached to the bicycle frame.

In accordance with an eighteenth aspect of the present invention, the derailleur according to the first aspect is configured so that the biasing member further has a second end portion. The intermediate member is configured to transmit the biasing force of the biasing member from the first end portion to the link member through the intermediate member. The movable member has a guiding surface and an arrangement portion. The guiding surface is configured to contact and guide a bicycle chain. The arrangement portion is configured to arrange the second end portion and provided on the guiding surface.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 is a side elevational view of a bicycle that is equipped with a derailleur in accordance with one embodiment;

FIG. 2 is an enlarged outer side elevational view of a portion of the bicycle in the area of the derailleur;

FIG. 3 is a rear perspective view of the derailleur illustrated in FIG. 2;

FIG. 4 is a cross-sectional view of the derailleur taken along line IV-IV of FIG. 3;

FIG. 5 is a cross-sectional view of the derailleur taken along line V-V of FIG. 3;

FIG. 6 is a rear perspective view of the derailleur illustrated in FIG. 2;

FIG. 7 is an exploded perspective view of a biasing mechanism of the derailleur illustrated in FIG. 6;

FIG. 8 is a perspective view of a first part of the biasing mechanism illustrated in FIG. 7;

FIG. 9 is a perspective view of the first part of the biasing mechanism illustrated in FIG. 7;

FIG. 10 is a cross-sectional view of the derailleur taken along line X-X of FIG. 6;

FIG. 11 is a partial perspective view of the derailleur illustrated in FIG. 6;

FIG. 12 is a partial perspective view of the derailleur illustrated in FIG. 6;

FIG. 13 is a schematic diagram illustrating the method of assembling the biasing mechanism of the derailleur illustrated in FIG. 6;

FIG. 14 is a schematic diagram illustrating the method of assembling the biasing mechanism of the derailleur illustrated in FIG. 6;

FIG. 15 is a schematic diagram illustrating the method of assembling the biasing mechanism of the derailleur illustrated in FIG. 6; and

FIG. 16 is a schematic diagram illustrating the method of assembling the biasing mechanism of the derailleur illustrated in FIG. 6.

DESCRIPTION OF THE EMBODIMENTS

The embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals designate corresponding or identical elements throughout the various drawings.

Referring initially to FIG. 1, a bicycle 10 is illustrated that is equipped with a derailleur 12 in accordance with one embodiment. As explained below, the derailleur 12 is a front derailleur configured to be attachable to a bicycle frame 14 in detachable and reinstallable manner. The bicycle 10 includes a front fork 16, a rear wheel 18, a front wheel 20, a handlebar 22, and a saddle 24. The handlebar 22 is attached to a steerer tube or steering column of the front fork 16. In the illustrated embodiment, a shifter 26 is attached to the handlebar 22 for operating the derailleur 12 to laterally shift a chain 28 between three front sprockets or chain rings 30. The shifter 26 is operatively connected to the derailleur 12 by an operation cable 32. It will be apparent to those skilled in the bicycle field from the present disclosure that any shifter that uses an electrical operation device to operate the derailleur 12 can be used instead of a mechanical operation device such as the shifter 26. Here, the shifter 26 is illustrated on the right side of the handlebar 22. However, the shifter 26 can be provided on either the left or right side of the handlebar 22 for operating the derailleur 12 as need and/or desired.

In this embodiment, the following directional terms “front”, “rear”, “forward”, “rearward”, “left”, “right”, “transverse”, “upward” and “downward” as well as any other similar directional terms refer to those directions which are determined on the basis of the rider who sits on the saddle 24 of the bicycle 10 with facing the handlebar 22, for example. Accordingly, these terms, as utilized to describe the derailleur 12, should be interpreted relative to the bicycle 10 as used in an upright riding position on a horizontal surface as illustrated in FIG. 1.

The bicycle 10 can be any type of bicycle and can have a variety of configurations. Since bicycles and their various components are well known in the bicycle field, the following specification does not include detailed descriptions and illustrations regarding the bicycle 10 and its various components other than the derailleur 12 of and the components or parts related to the derailleur 12. In other words, this specification describes and/or illustrates only the derailleur 12 and the components or parts of the bicycle 10 that is related to the derailleur 12.

Referring to FIG. 2, the derailleur 12 is mounted on a seat tube 34 of the bicycle frame 14. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the derailleur 12 can be attached to a hanger tube 36 of the bicycle frame 14 by a bottom bracket or other mounting structure, if needed and/or desired. Furthermore, the configurations of the derailleur 12 can be applied to a rear derailleur if needed and/or desired.

As seen in FIG. 2, the bicycle 10 has a crank axis A1 and a rear wheel axis A2 which is parallel to the crank axis A1. The crank axis A1 is defined by the hanger tube 36 of the bicycle frame 14. In other words, the crank axis A1 corresponds to a center longitudinal axis of the hanger tube 36 and thus also corresponds to the center of rotation of the chain rings 30. As seen in FIG. 2, the rear wheel axis A2 is defined by a center axle 38 of the rear wheel 18.

As illustrated in FIG. 2, the derailleur 12 comprises a base member 40, a movable member 42, a link member 44, an additional link member 46, and a biasing mechanism 48. The base member 40 is made of a rigid material such as a metal material or a fiber reinforced material. The base member 40 is configured to be attached to the bicycle frame 14. In the illustrated embodiment, the base member 40 is attached to the seat tube 34 of the bicycle frame 14 such that a position of the base member 40 with respect to the seat tube 34 is adjustable in an adjustment direction D1. More specifically, the base member 40 includes a clamp portion 41 configured to be attached to the seat tube 34. The adjustment direction D1 is defined along a center axis A3 of the seat tube 34. It will be apparent to those skilled in the bicycle field from the present disclosure that the base member 40 can have other configurations as needed and/or desired. For example, the base member 40 can be attached to the hanger tube 36 by the bottom bracket if needed and/or desired.

As illustrated in FIG. 2, the operation cable 32 includes an outer casing 32 a and an inner cable 32 b passing through the outer casing 32 a. Thus, in the illustrated embodiment, the operation cable 32 is a conventional Bowden cable. For example, the inner cable 32 b is slidably disposed inside the outer casing 32 a. The inner cable 32 b is attached to the link member 44.

As illustrated in FIG. 3, the movable member 42 is configured to be movable with respect to the base member 40 between a retracted position P1 and an extended position P2 at which the movable member 42 is farther from the base member 40 than the retracted position P1. The movable member 42 is a chain guide configured to guide the chain 28. The movable member 42 (the first member 50 and/or the second member 52) is made of a rigid material such as a metal material or a resin material. For example, the movable member 42 (the first member 50 and/or the second member 52) is made of aluminum, an aluminum alloy, iron, stainless steel, or a synthetic resin material.

The movable member 42 comprises a first member 50 and a second member 52. The first member 50 and the second member 52 are made of a metallic material such as aluminum, an aluminum alloy, iron, or stainless steel. It will be apparent to those skilled in the bicycle field from the present disclosure that the first member 50 can be made of a material different from a material of the second member 52.

The first member 50 is configured to contact and to laterally shift the chain 28 such that the chain 28 is moved in an outward direction D21 away from the bicycle frame 14 between the chain rings 30. The outward direction D21 is one of a transverse direction D2 of the bicycle frame 14. The first member 50 includes a first guide portion 50 a and a first connecting portion 50 b. The first connecting portion 50 b protrudes from the first guide portion 50 a. The first connecting portion 50 b is bent from an end part of the first guide portion 50 a. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the first connecting portion 50 b does not need to protrude from the first guide portion 50 a. The first connecting portion 50 b does not need to be bent from the first guide portion 50 a. The first connecting portion 50 b can have other configurations as needed and/or desired. For example, the first connecting portion 50 b can be a separate member from the first guide portion 50 a and can be connected with the first guide portion 50 a using other suitable attaching structures such as welding, riveting or bolting if needed and/or desired.

The second member 52 is configured to contact and to laterally shift the chain 28 such that the chain 28 is moved in an inward direction D22 toward the bicycle frame 14 between the chain rings 30. The inward direction D22 is the other of the transverse direction D2 and is opposite to the outward direction D21. The second member 52 includes a second guide portion 52 a and a second connecting portion 52 b to overlap the first connecting portion 50 b. The second connecting portion 52 b protrudes from the second guide portion 52 a toward the first guide portion 50 a. The second connecting portion 52 b is bent from an end part of the second guide portion 52 a. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the second connecting portion 52 b does not need to protrude from the second guide portion 52 a. The second connecting portion 52 b does not need to be bent from the second guide portion 52 a. The second connecting portion 52 b can have other configurations as needed and/or desired. For example, the second connecting portion 52 b can be a separate member from the second guide portion 52 a and can be connected with the second guide portion 52 a using other suitable attaching structures such as welding, riveting or bolting if needed and/or desired.

In the illustrated embodiment, the first member 50 is disposed closer to the bicycle frame 14 than the second member 52. The first guide portion 50 a is disposed closer to the bicycle frame 14 than the second guide portion 52 a. The first guide portion 50 a is spaced apart from the second guide portion 52 a to define a chain guiding slot 42 a through which the chain 28 extends in a chain driving direction D3. The chain driving direction D3 is defined with respect to the derailleur 12 as a direction in which the chain 28 is driven by the rider's pedaling force to forwardly move the bicycle 10.

The second member 52 further includes a third connecting portion 52 c. The third connecting portion 52 c is disposed at a lower end portion of the second guide portion 52 a. The third connecting portion 52 c is coupled to a lower end portion of the first guide portion 50 a by a fastener 54 (e.g., a rivet). In the illustrated embodiment, the first member 50 and the second member 52 are separate members from one another. It will be apparent to those skilled in the bicycle field from the present disclosure that the first member 50 can be provided integrally with the second member 52 as a one-piece unitary member. For example, the third connecting portion 52 c can be provided integrally with the lower end portion of the first guide portion 50 a as a one-piece unitary member. Furthermore, the first connecting portion 50 b can be provided integrally with the second connecting portion 52 b as a one-piece unitary member.

As illustrated in FIG. 3, the first connecting portion 50 b and the second connecting portion 52 b are provided at an upper end portion of the movable member 42. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the first connecting portion 50 b and the second connecting portion 52 b can be provided at a portion other than the upper end portion of the movable member 42. The first connecting portion 50 b is disposed at an upper end portion of the first guide portion 50 a. The second connecting portion 52 b is disposed at an upper end portion of the second guide portion 52 a. In the illustrated embodiment, the first connecting portion 50 b is provided under the second connecting portion 52 b.

As illustrated in FIG. 4, the first connecting portion 50 b is coupled to the second connecting portion 52 b by a fastener 55 and a shaft member 56. The fastener 55 is a rivet, for example. The shaft member 56 is configured to couple the first connecting portion 50 b to the second connecting portion 52 b and configured to rotatably couple the movable member 42 to the additional link member 46. Since the shaft member 56 rotatably couples the movable member 42 to the additional link member 46 in addition to coupling the first connecting portion 50 b to the second connecting portion 52 b, the structure of the derailleur 12 can be simplified. It will be apparent to those skilled in the bicycle field from the present disclosure that the shaft member 56 does not need to rotatably couple the movable member 42 to the additional link member 46. The shaft member 56 can be merely couples the first connecting portion 50 b to the second connecting portion 52 b if the other member rotatably couples the movable member 42 to the additional link member 46.

The shaft member 56 includes a shaft main body 56 a, a first flange 56 b, a second flange 57, and a third flange 56 c. The shaft member 56 is made of a rigid material such as a metallic material. The shaft member 56 is made of aluminum, an aluminum alloy, iron, or stainless steel, for example. The shaft main body 56 a extends along the first rotation axis A11.

The first flange 56 b is provided at a lower end of the shaft main body 56 a. The first flange 56 b has an outer diameter larger than an outer diameter of the lower end of the shaft main body 56 a. The first flange 56 b is a caulked portion and is provided integrally with the shaft main body 56 a as a one-piece unitary member. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the first flange 56 b can have other configurations instead of the caulked portion. The first flange 56 b can be a separate member from the shaft main body 56 a as well as the second flange 57. The first flange 56 b can be a separate member such as a snap ring or a nut configured to be detachably attached to the shaft main body 56 a, for example.

The second flange 57 is a snap ring configured to be detachably attached to the shaft main body 56 a. The second flange 57 is provided in an attachment groove 56 d provided at an upper end of the shaft main body 56 a. The second flange 57 has an outer diameter larger than an outer diameter of the upper end of the shaft main body 56 a. The second flange 57 prevents the additional link member 46 from being removed from the shaft member 56. It will be apparent to those skilled in the bicycle field from the present disclosure that the second flange 57 can have other configurations instead of the snap ring. For example, the second flange 57 can be a nut. Furthermore, the second flange 57 can be integrally provided with the shaft main body 56 a as a one-piece unitary member. The second flange 57 can be a caulked portion as well as the first flange 56 b, for example.

The third flange 56 c is provided between the first flange 56 b and the second flange 57. The third flange 56 c has an outer diameter larger than an outer diameter of the shaft main body 56 a. The third flange 56 c is provided integrally with the shaft main body 56 a as a one-piece unitary member. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the third flange 56 c can have other configurations. The third flange 56 c can be a separate member such as a snap ring configured to be detachably attached to the shaft main body 56 a. Furthermore, it will be apparent to those skilled in the bicycle field from the present disclosure that the third flange 56 c can be omitted if needed and/or desired.

The additional link member 46 includes a first link through-hole 46 a through which the shaft member 56 extends. A bush 47 is attached to the shaft member 56 and is provided in the first link through-hole 46 a. The first connecting portion 50 b includes a first through-hole 50 i. The second connecting portion 52 b includes a second through-hole 52 d. The shaft member 56 extends through the first through-hole 50 i and the second through-hole 52 d. An outer diameter of the first flange 56 b is larger than inner diameters of the first through-hole 50 i and the second through-hole 52 d. An outer diameter of the second flange 57 is larger than an inner diameter of the first link through-hole 46 a. An outer diameter of the third flange 56 c is larger than the inner diameters of the first through-hole 50 i, the second through-hole 52 d and the first link through-hole 46 a. It will be apparent to those skilled in the bicycle field from the present disclosure that the first through-hole 50 i can be a recess or a cutout through which the shaft member 56 extends instead of the first through-hole 50 i. Furthermore, the second through-hole 52 d can be a recess or a cutout through which the shaft member 56 extends instead of the second through-hole 52 d.

The first connecting portion 50 b, the second connecting portion 52 b, and the additional link member 46 are provided between the first flange 56 b and the second flange 57. The first connecting portion 50 b and the second connecting portion 52 b are provided between the first flange 56 b and the additional link member 46. More specifically, the first connecting portion 50 b and the second connecting portion 52 b are provided between the first flange 56 b and the third flange 56 c. The additional link member 46 is provided between the third flange 56 c and the second flange 57. The first connecting portion 50 b is secured to the second connecting portion 52 b using the first flange 56 b and the third flange 56 c to integrally provide the movable member 42. The first connecting portion 50 b and the second connecting portion 52 b are sandwiched between the first flange 56 b and the third flange 56 c without any gaps. On the other hand, the additional link member 46 is rotatably provided relative to the movable member 42 between the second flange 57 and the third flange 56 c. The additional link member 46 is sandwiched between the second flange 57 and the third flange 56 c with a gap to be rotatable relative to the movable member 42. In the illustrated embodiment, the second connecting portion 52 b of the second member 52 is provided between the additional link member 46 and the first connecting portion 50 b of the first member 50. It will be apparent to those skilled in the bicycle field from the present disclosure that the first connecting portion 50 b can be provided between the additional link member 46 and the second connecting portion 52 b. The first connecting portion 50 b is configured to contact the second connecting portion 52 b. It will be apparent to those skilled in the bicycle field from the present disclosure that at least one intermediate member can be provided between the first connecting portion 50 b and the second connecting portion 52 b.

As illustrated in FIG. 4, the shaft member 56 is provided on an upstream side of the fastener 55 in the chain driving direction D3. The terms “upstream” and “downstream” as used herein is defined with respect to the chain driving direction D3. The first connecting portion 50 b includes an upstream end portion 50 j and a downstream end portion 50 k. The downstream end portion 50 k is disposed downstream of the upstream end portion 50 j in the chain driving direction D3. The shaft member 56 is disposed closer to the upstream end portion 50 j than the downstream end portion 50 k in the chain driving direction D3 in state where the base member 40 is attached to the bicycle frame 14. It will be apparent to those skilled in the bicycle field from the present disclosure that the shaft member 56 can be disposed at other positions within the first connecting portion 50 b and the second connecting portion 52 b. The shaft member 56 can be disposed closer to the downstream end portion 50 k than the upstream end portion 50 j in the chain driving direction D3, for example.

As illustrated in FIG. 5, the additional link member 46 is configured to movably couple the movable member 42 to the base member 40. More specifically, the additional link member 46 is configured to couple the movable member 42 to the base member 40 such that the movable member 42 is movable with respect to the base member 40 between the retracted position P1 and the extended position P2. The additional link member 46 includes a first link end portion 46 b and a second link end portion 46 c. The second link end portion 46 c is opposite to the first link end portion 46 b. The first link end portion 46 b is rotatably coupled to the movable member 42 about a first rotation axis A11 by the shaft member 56. The second link end portion 46 c is rotatably coupled to the base member 40 about a second rotation axis A12 by a first link shaft 58.

As illustrated in FIG. 5, the link member 44 is configured to movably couple the movable member 42 to the base member 40. More specifically, the link member 44 is configured to rotatably couple the first member 50 to the base member 40. The link member 44 is rotatably coupled to the base member 40 about a third rotation axis A13 by a rotational axle 60. The movable member 42 is pivotally connected to the link member 44 via the rotational axle 60. The link member 44 is rotatably coupled to the base member 40 about a fourth rotation axis A14 by a second link shaft 62. As seen in FIG. 5, the link member 44 is configured to couple the movable member 42 to the base member 40 such that the base member 40, the movable member 42, the link member 44, and the additional link member 46 define a four-bar linkage. It will be apparent to those skilled in the bicycle field from the present disclosure that other linkage structures can be applied to the derailleur 12.

When viewed along the crank axis A1 as illustrated in FIG. 2, the first rotation axis A11, the second rotation axis A12, the third rotation axis A13, and the fourth rotation axis A14 are substantially parallel to one another. When viewed along the crank axis A1, the first rotation axis A11, the second rotation axis A12, the third rotation axis A13, and the fourth rotation axis A14 are not parallel and not orthogonal to the adjustment direction D1 in a state where the derailleur 12 is attached to the bicycle frame 14 to properly shift the chain 28. When viewed along the crank axis A1, the first rotation axis A11, the second rotation axis A12, the third rotation axis A13, and the fourth rotation axis A14 are inclined with respect to the adjustment direction D1 at a first angle B1 in a state where the derailleur 12 is attached to the bicycle frame 14 to properly shift the chain 28. The first angle B1 can be set within a range between approximately zero degree and approximately 30 degrees, for example. Furthermore, when viewed along the crank axis A1, the first rotation axis A11, the second rotation axis A12, the third rotation axis A13, and the fourth rotation axis A14 are inclined with respect to a virtual plane E at a second angle B2 in a state where the derailleur 12 is attached to the bicycle frame 14 to properly shift the chain 28. The second angle B2 can be set within a range between approximately 80 degrees and approximately 100 degrees, for example. The virtual plane E is defined to be parallel to the crank axis A1 and the rear wheel axis A2.

Returning to FIG. 5, the link member 44 is configured to move in a forward-rearward direction D4 of the bicycle frame 14 when the movable member 42 moves between the retracted position P1 and the extended position P2. When viewed from a vertical direction of the bicycle frame 14, the forward-rearward direction D4 substantially coincides with the chain driving direction D3 in a state where the derailleur 12 is attached to the bicycle frame 14. The link member 44 is arranged closer to the bicycle frame 14 than the additional link member 46 when the base member 40 is attached to the bicycle frame 14. The link member 44 includes a cable attachment portion 65 to which the operation cable 32 is to be attached. The cable attachment portion 65 is configured to be pulled via the operation cable 32 in a forward direction D41 of the bicycle frame 14. The forward direction D41 is one of the forward-rearward direction D4.

When the cable attachment portion 65 is pulled via the operation cable 32 in the forward direction D41, the link member 44 is rotated with respect to the base member 40 about the fourth rotation axis A14. This causes the movable member 42 to be moved from the retracted position P1 to the extended position P2 in the forward direction D41 against the biasing force of the biasing mechanism 48. More specifically, the movable member 42 is moved from the retracted position P1 to the extended position P2 in the forward direction D41 and moved in the outward direction D21 away from the bicycle frame 14 by pulling the operation cable 32.

When the pulling force of the operation cable 32 is released, the movable member 42 is moved from the extended position P2 to the retracted position P1. More specifically, the movable member 42 is moved from the extended position P2 to the retracted position P1 in a rearward direction D42 and moved in the inward direction D22 by releasing the operation cable 32. In this way, the movable member 42 selectively positions the chain 28 over one of the chain rings 30 in response to the operation of the shifter 26. The rearward direction D42 is the other of the forward-rearward direction D4 and is opposite to the forward direction D41.

It will be apparent to those skilled in the bicycle field from the present disclosure that the movable member 42 can be configured to move away from the base member 40 in the rearward direction D42 of the bicycle frame 14 when the movable member 42 moves from the retracted position P1 to the extended position P2. It will be apparent to those skilled in the bicycle field from the present disclosure that the cable attachment portion 65 can be mounted on the additional link member 46. Furthermore, an electric driving apparatus can be applied to the derailleur 12 to move the movable member 42 relative to the base member 40 instead of the operation cable 32 and the cable attachment portion 65.

As illustrated in FIG. 5, the shaft member 56 is configured to move away from the base member 40 in the forward direction D41 of the bicycle frame 14 when the movable member 42 moves from the retracted position P1 to the extended position P2. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the shaft member 56 can be configured to move away from the base member 40 in the rearward direction D42 of the bicycle frame 14 when the movable member 42 moves from the retracted position P1 to the extended position P2. Since the shaft member 56 is movable relative to the base member 40 in the forward-rearward direction D4, a connecting part at which the first connecting portion 50 b is connected with the second connecting portion 52 b can be disposed on a rotation axis (i.e., the first rotation axis A11) of the movable member 42 and the additional link member 46. This allows the shaft member 56 to function as both the rotation axis and the connecting part.

As illustrated in FIG. 5, end shift stage positions of the movable member 42 with respect to the base member 40 are adjustable by turning a low shift stage adjustment screw 63 a and a top shift stage adjustment screw 63 b. In this way, the range of movement of the movable member 42 is adjustable with respect to the base member 40. In particular, the low shift stage adjustment screw 63 a contacts an abutment of the additional link member 46 when the movable member 42 is located in the low shift stage (gear) position (i.e., the retracted position P1). The top shift stage adjustment screw 63 b contacts an abutment of the additional link member 46 when the movable member 42 is located in the top shift stage (gear) position (i.e., the extended position P2). In the illustrated embodiment, the abutment of the additional link member 46 is pressed against the low shift stage adjustment screw 63 a by the biasing force of the biasing mechanism 48.

As illustrated in FIG. 6, the biasing mechanism 48 is configured to bias (press) the link member 44 such that the movable member 42 is disposed at one of the retracted position P1 and the extended position P2. In the illustrated embodiment, the biasing mechanism 48 is configured to bias the link member 44 such that the movable member 42 is disposed at the retracted position P1. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the biasing mechanism 48 can be configured to bias the link member 44 such that the movable member 42 is disposed at the extended position P2.

The biasing mechanism 48 comprises a biasing member 64, an intermediate member 66, and a support member 68. The biasing member 64 has a first end portion 64 b and a second end portion 64 c. The intermediate member 66 is separately provided from the movable member 42 and the link member 44 so as to transmit biasing force of the biasing member 64 from the first end portion 64 b to one of the movable member 42 and the link member 44 through the intermediate member 66. In the illustrated embodiment, the intermediate member 66 is configured to transmit the biasing force of the biasing member 64 from the first end portion 64 b to the link member 44. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the intermediate member 66 can be configured to transmit the biasing force of the biasing member 64 from the first end portion 64 b to the movable member 42. The biasing member 64, the intermediate member 66, and the support member 68 are configured to be rotatable with respect to the movable member 42 and the link member 44 about the third rotation axis A13.

As illustrated in FIG. 5, the intermediate member 66 is provided on a first side S1 of the movable member 42. The first side S1 is opposite to a second side S2 of the movable member 42 and is closer to the bicycle frame 14 than the second side S2 in a state where the base member 40 is attached to the bicycle frame 14. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the intermediate member 66 can be provided on the second side S2 of the movable member 42. The intermediate member 66 is provided above the biasing member 64. The support member 68 is provided under the biasing member 64. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the intermediate member 66 can be provided under the biasing member 64 and that the support member 68 can be provided above the biasing member 64.

As illustrated in FIG. 7, the biasing member 64 comprises a torsion spring including a cylindrical part 64 a to generate biasing force around the third rotation axis A13. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the biasing member 64 can be a member configured to generate biasing force other than the torsion spring. The first end portion 64 b extends from the cylindrical part 64 a along the third rotation axis A13. The second end portion 64 c extends from the cylindrical part 64 a along a radial direction of the cylindrical part 64 a. In the illustrated embodiment, the first end portion 64 b is provided at an upper end portion of the cylindrical part 64 a, and the second end portion 64 c is provided at a lower end portion of the cylindrical part 64 a. The first end portion 64 b is configured to engage with the intermediate member 66. The second end portion 64 c is configured to engage with the movable member 42. The cylindrical part 64 a of the biasing member 64, the intermediate member 66, and the support member 68 are arranged on the rotational axle 60.

The intermediate member 66 includes a first part 70 and a second part 72. The first part 70 is configured to engage with the first end portion 64 b of the biasing member 64. The second part 72 is configured to engage with the one of the link member 44 and the movable member 42 and is configured to be detachably attached to the first part 70. In the illustrated embodiment, the second part 72 comprises a pin configured to engage with a pin engaging opening 76 e (FIG. 9) which will be described later.

The first part 70 includes an inside portion 74 and an outside portion 76. The inside portion 74 is configured to be provided inside the cylindrical part 64 a of the biasing member 64. The inside portion 74 protrudes from the outside portion 76 along the third rotation axis A13. The inside portion 74 is configured to contact an inner peripheral surface of the cylindrical part 64 a in a radial direction. The outside portion 76 is configured to be provided outside the cylindrical part 64 a. The outside portion 76 is configured to engage with the first end portion 64 b of the biasing member 64. The outside portion 76 is configured to contact an upper end surface of the cylindrical part 64 a in an axial direction. The second part 72 is configured to be detachably attached to the outside portion 76. In the illustrated embodiment, the first part 70 is made of a rigid material such as a metallic material. The first part 70 is made of aluminum, an aluminum alloy, iron, or stainless steel, for example. Similarly, the second part 72 is made of a rigid material such as a metallic material. The second part 72 is made of aluminum, an aluminum alloy, iron, or stainless steel, for example.

The first part 70 includes a through-hole 70 a through which the rotational axle 60 extends. The through-hole 70 a extends along the third rotation axis A13 and is provided in the inside portion 74 and the outside portion 76. In the illustrated embodiment, a bush 78 extends through the through-hole 70 a. The rotational axle 60 extends through the bush 78.

The outside portion 76 includes an engagement groove 76 a with which the first end portion 64 b of the biasing member 64 engages. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the inside portion 74 can be configured to engage with the first end portion 64 b of the biasing member 64 instead of the outside portion 76. It will be apparent to those skilled in the bicycle field from the present disclosure that the inside portion 74 can be omitted.

The support member 68 is configured to support a lower end portion of the biasing member 64. The support member 68 is provided on an opposite side of the intermediate member 66 with respect to the biasing member 64. In the illustrated embodiment, the support member 68 is made of a rigid material such as a metallic material. The support member 68 is made of aluminum, an aluminum alloy, iron, or stainless steel, for example. The support member 68 includes an end support portion 68 a, an intermediate portion 68 b, and an inner support portion 68 c.

The end support portion 68 a is configured to be provided outside the cylindrical part 64 a of the biasing member 64. The end support portion 68 a is configured to contact a lower end surface of the biasing member 64 in an axial direction D5 of the rotational axle 60. The axial direction D5 is parallel to the third rotation axis A13. The intermediate portion 68 b and the inner support portion 68 c are configured to be provided inside of the cylindrical part 64 a. The support member 68 includes a through-hole 68 d extending along the third rotation axis A13. The rotational axle 60 extends through the through-hole 68 d along the third rotation axis A13. It will be apparent to those skilled in the bicycle field from the present disclosure that the support member 68 can be omitted if needed and/or desired.

As illustrated in FIG. 8, the outside portion 76 includes a tool engagement portion 76 b with which a tool is to engage when the derailleur 12 is assembled. The tool engagement portion 76 b comprises a plurality of tool engaging openings 76 c and 76 d with which the tool is to engage when the derailleur 12 is assembled. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the tool engagement portion 76 b can comprise at least one tool engaging opening with which the tool is to engage when the derailleur 12 is assembled.

Each of the tool engaging openings 76 c and 76 d extends in a radial direction of the outside portion 76. The radial direction of the outside portion 76 is perpendicular to the third rotation axis A13. Each of the tool engaging openings 76 c and 76 d is an elongated through-hole. However, it will be apparent to those skilled in the bicycle field from the present disclosure that each of the tool engaging openings 76 c and 76 d can have other configurations such as a bottomed hole, a recess, or a groove instead of a through-hole. In the illustrated embodiment, the tool engaging openings 76 c and 76 d have the same shape as each other. It will be apparent to those skilled in the bicycle field from the present disclosure that the tool engaging openings 76 c and 76 d can have different shapes from each other.

As illustrated in FIGS. 8 and 9, each of the tool engaging openings 76 c and 76 d extends from an outer periphery of the outside portion 76 to the through-hole 70 a. The tool engaging opening 76 c is spaced apart from the tool engaging opening 76 d in a circumferential direction of the outside portion 76. In the illustrated embodiment, the tool engaging opening 76 c is closer to the engagement groove 76 a than the tool engaging opening 76 d.

As illustrated in FIG. 9, the outside portion 76 further includes the pin engaging opening 76 e. The pin engaging opening 76 e is a through-hole extending in the radial direction of the outside portion 76 from the outer periphery of the outside portion 76 to the through-hole 70 a. The second part 72 (FIG. 7) engages with the pin engaging opening 76 e. The second part (pin) 72 is inserted into the pin engaging opening 76 e when the derailleur 12 is assembled. It will be apparent to those skilled in the bicycle field from the present disclosure that the pin engaging opening 76 e can have other configurations such as a bottomed hole, a recess, or a groove instead of a through-hole.

As illustrated in FIG. 10, the inside portion 74 has a first outer diameter L1. The outside portion 76 has a second outer diameter L2 which is larger than the first outer diameter L1. The end support portion 68 a has a third outer diameter L3. The intermediate portion 68 b has a fourth outer diameter L4. The inner support portion 68 c has a fifth outer diameter L5. The third outer diameter L3 is larger than the fourth outer diameter L4 and the fifth outer diameter L5. The fourth outer diameter L4 is larger than the fifth outer diameter L5. The third outer diameter L3 is substantially the same as the second outer diameter L2. The cylindrical part 64 a of the biasing member 64 has a sixth outer diameter L6 and an inner diameter L7. The second outer diameter L2 and the third outer diameter L3 are substantially the same as the sixth outer diameter L6 and are larger than the inner diameter L7.

As illustrated in FIG. 10, the link member 44 includes distal end portions 80 a and 80 b. The distal end portions 80 a and 80 b are pivotally connected to the movable member 42. The distal end portion 80 b is spaced apart from the distal end portion 80 a along the third rotation axis A13. Each of the distal end portions 80 a and 80 b is pivotally connected to the movable member 42 about the third rotation axis A13 by the rotational axle 60. The biasing mechanism 48 is provided between the distal end portions 80 a and 80 b in the axial direction D5. The outside portion 76 is provided between the biasing member 64 and the link member 44 in the axial direction D5 of the rotational axle 60. More specifically, the outside portion 76 is provided between the distal end portion 80 a and the biasing member 64 (the cylindrical part 64 a) in the axial direction D5. The end support portion 68 a is provided between the distal end portion 80 b and the biasing member 64 (the cylindrical part 64 a).

The first member 50 of the movable member 42 includes a first support portion 50 c and a second support portion 50 d. The second support portion 50 d is spaced apart from the first support portion 50 c along the third rotation axis A13. The distal end portion 80 a is pivotally connected to the first support portion 50 c about the third rotation axis A13 by the rotational axle 60. The distal end portion 80 b is pivotally connected to the second support portion 50 d about the third rotation axis A13 by the rotational axle 60. The distal end portions 80 a and 80 b are provided between the first support portion 50 c and the second support portion 50 d along the third rotation axis A13.

The first support portion 50 c includes a first support through-hole 50 e. The distal end portion 80 a includes a through-hole 80 c. The rotational axle 60 extends through the first support through-hole 50 e and the through-hole 80 c. The bush 78 is provided in the through-hole 80 c. The second support portion 50 d includes a second support through-hole 50 f. The distal end portion 80 b includes a through-hole 80 d. The rotational axle 60 extends through the second support through-hole 50 f and the through-hole 80 d. A bush 82 is attached to the rotational axle 60 and is provided in the through-hole 80 d.

As illustrated in FIG. 5, the link member 44 is configured such that the distal end portions 80 a and 80 b move in the forward-rearward direction D4 of the bicycle frame 14 when the movable member 42 moves between the retracted position P1 and the extended position P2. In the illustrated embodiment, the link member 44 is configured such that the distal end portions 80 a and 80 b move in the forward direction D41 of the bicycle frame 14 when the movable member 42 moves from the retracted position P1 to the extended position P2.

As illustrated in FIG. 11, the link member 44 includes proximal end portions 78 a and 78 b. The proximal end portions 78 a and 78 b are pivotally connected to the base member 40. The proximal end portions 78 a and 78 b are provided on an opposite side of the distal end portions 80 a and 80 b in the link member 44. The proximal end portion 78 b is spaced apart from the proximal end portion 78 a along the fourth rotation axis A14. Each of the proximal end portions 78 a and 78 b is pivotally connected to the base member 40 about the fourth rotation axis A14 by the second link shaft 62.

As illustrated in FIG. 11, the link member 44 includes a recessed portion 44 a configured to engage with the second part 72. The second part 72 is provided in the recessed portion 44 a. The recessed portion 44 a is also configured to prevent the second part 72 from being unintentionally removed from the outer portion 76 of the first part 70. The biasing force of the biasing member 64 is transmitted from the first end portion 64 b of the biasing member 64 to the link member 44 through the outside portion 76 and the second part 72.

As illustrated in FIG. 12, the first member 50 of the movable member 42 includes an opening 50 m provided adjacent to the biasing mechanism 48. The first member 50 further includes an arrangement portion 50 g configured to arrange the second end portion 64 c and provided on a guiding surface 50 h. The arrangement portion 50 g comprises a recess in which the second end portion 64 c is disposed. The guiding surface 50 h is provided to slide with the chain 28 and faces the second guide portion 52 a of the second member 52. The second end portion 64 c of the biasing member 64 is configured to engage with the guiding surface 50 h. More specifically, the second end portion 64 c is provided inside the arrangement portion 50 g and does not protrude from the guiding surface 50 h toward the second guide portion 52 a. This prevents the second end portion 64 c from interfering with the chain 28. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the arrangement portion 50 g can be omitted if needed and/or desired. Since the second end portion 64 c engages with the guiding surface 50 h, the second end portion 64 c and/or a support part engaging with the second end portion 64 c do not protrude towards the bicycle frame 14 and/or the rear wheel 18. This makes the derailleur 12 compact in the transverse direction D2 of the bicycle frame 14, allowing a desired distance to be ensured between the derailleur 12 and the rear wheel 18 even if a size (e.g., a width) of the rear wheel 18 needs to be greater. Thus, the derailleur 12 can be prevented from interfering with the rear wheel 18 regardless of the size of the rear wheel 18.

Unlike the first end portion 64 b of the biasing member 64, the biasing force of the biasing member 64 is directly transmitted from the second end portion 64 c of the biasing member 64 to the first member 50 of the movable member 42. However, it will be apparent to those skilled in the bicycle field from the present disclosure that the intermediate member 66 can be applied to the second end portion of the biasing member 64. In such embodiment, the intermediate member 66 is provided at the lower end portion of the biasing member 64 instead of the support member 68, and the second part 72 is arranged at the arrangement portion 50 g of the first member 50.

Referring to FIGS. 13 to 16, the method of assembling the biasing mechanism 48 will be described below.

As illustrated in FIG. 13, the first end portion 64 b of the biasing member 64 is provided in the engaging groove 76 a of the outside portion 76 of the first part 70. In the state depicted in FIG. 11, the biasing member 64 is a free state, and the biasing force of the biasing member 64 is not applied to the outside portion 76. The initial circumferential position of the tool engaging opening 76 c with respect to the link member 44 is set to a position at which the first tool 100 can be inserted into the tool engaging opening 76 c, for example.

As illustrated in FIG. 13, a first tool 100 is inserted into the tool engaging opening 76 c of the outside portion 76. The first part 70 is rotated in a first rotation direction D61 by the worker using the first tool 100, increasing the biasing force F1 of the biasing member 64. The first part 70 is held against the biasing force F1 by the worker using the first tool 100 at the circumferential position depicted in FIG. 14.

As illustrated in FIG. 14, when the tool engaging opening 76 d is moved to a position at which a second tool 102 can be inserted into the tool engaging opening 76 d, the second tool 102 is inserted into the tool engaging opening 76 d. After the second tool 102 is inserted into the tool engaging opening 76 d, the first tool 100 is removed from the tool engaging opening 76 c. At this time, the first part 70 is held against the biasing force F1 by the worker using the second tool 102 at the circumferential position depicted in FIG. 14.

As illustrated in FIG. 15, the first part 70 is further rotated in the first rotation direction D61 by the worker using the second tool 102. When the pin engaging opening 76 e is moved to a position at which the second part (pin) 72 can be inserted into the pin engaging opening 76 e, the second part 72 is inserted into the pin engaging opening 76 e.

As illustrated in FIG. 16, the first part 70 is rotated in a second rotation direction D62 by the worker using the second tool 102, allowing the second part 72 to contact an inclined surface 44 b of the recessed portion 44 a. The second rotation direction D62 is opposite to the first rotation direction D61. In a state where the second part 72 contacts the inclined surface 44 b, the second tool 102 is removed from the tool engaging opening 76 d. The biasing force F2 is transmitted from the biasing member 64 to the link member 44 through the first part 70 and the second part 72 of the intermediate member 66.

As discussed above, the intermediate member 66 is separately provided from the movable member 42 and the link member 44 so as to transmit the biasing force F2 of the biasing member 64 from the first end portion 64 b to the link member 44 through the intermediate member 66. This allows the biasing mechanism 48 to be easily assembled using the first tool 100 and the second tool 102, comparing with a derailleur in which the intermediate member 66 is not provided.

The term “comprising” and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, components, groups, integers, and/or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers and/or steps. This concept also applies to words of similar meaning, for example, the terms “have”, “include” and their derivatives.

The terms “member”, “section”, “portion”, “part” or “element” when used in the singular can have the dual meaning of a single part or a plurality of parts.

The ordinal numbers in the terms “first”, “second” or the like recited in the present application are merely identifiers, but do not have any other meanings, for example, a particular order and the like. Moreover, for example, the term “first element” itself does not imply an existence of “second element”, and the term “second element” itself does not imply an existence of “first element.”

Finally, terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed.

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. 

1. A derailleur comprising: a base member configured to be attached to a bicycle frame; a movable member configured to be movable with respect to the base member between a retracted position and an extended position at which the movable member is farther from the base member than the retracted position; a link member configured to movably couple the movable member to the base member; and a biasing mechanism configured to bias the link member such that the movable member is disposed at one of the retracted position and the extended position, the biasing mechanism comprising: a biasing member having a first end portion; and an intermediate member separately provided from the movable member and the link member so as to transmit biasing force of the biasing member from the first end portion to one of the movable member and the link member through the intermediate member.
 2. The derailleur according to claim 1, wherein the intermediate member is configured to transmit the biasing force of the biasing member from the first end portion to the link member.
 3. The derailleur according to claim 1, wherein the biasing mechanism is configured to bias the link member such that the movable member is disposed at the retracted position.
 4. The derailleur according to claim 1, wherein the intermediate member includes a first part and a second part, the first part is configured to engage with the first end portion of the biasing member, and, the second part is configured to engage with the one of the link member and the movable member and is configured to be detachably attached to the first part.
 5. The derailleur according to claim 4, wherein the biasing member comprises a torsion spring including a cylindrical part from which the first end portion extends, the first part includes an inside portion configured to be provided inside the cylindrical part, and an outside portion configured to be provided outside the cylindrical part, and the second part is configured to be detachably attached to the outside portion.
 6. The derailleur according to claim 5, wherein the movable member is pivotally connected to the link member via a rotational axle, and the cylindrical part of the biasing member and the intermediate member are arranged on the rotational axle.
 7. The derailleur according to claim 6, wherein the outside portion is configured to engage with the first end portion of the biasing member.
 8. The derailleur according to claim 7, wherein the inside portion has a first outer diameter, and the outside portion has a second outer diameter which is larger than the first outer diameter.
 9. The derailleur according to claim 6, wherein the outside portion is provided between the biasing member and the link member in an axial direction of the rotational axle.
 10. The derailleur according to claim 5, wherein the outside portion includes a tool engagement portion with which a tool is to engage when the derailleur is assembled.
 11. The derailleur according to claim 10, wherein the tool engagement portion comprises at least one tool engaging opening with which the tool is to engage when the derailleur is assembled.
 12. The derailleur according to claim 10, wherein the tool engagement portion comprises a plurality of tool engaging openings with which the tool is to engage when the derailleur is assembled.
 13. The derailleur according to claim 10, wherein the outside portion further includes a pin engaging opening, and the second part comprises a pin configured to engage with the pin engaging opening.
 14. The derailleur according to claim 4, wherein the intermediate member is configured to transmit the biasing force of the biasing member from the first end portion to the link member, and the link member includes a recessed portion configured to engage with the second part.
 15. The derailleur according to claim 1, wherein the link member includes a proximal end portion pivotally connected to the base member and a distal end portion pivotally connected to the movable member, and the link member is configured such that the distal end portion moves in a forward-rearward direction of the bicycle frame when the movable member moves between the retracted position and the extended position.
 16. The derailleur according to claim 1, further comprising: an additional link member configured to couple the movable member to the base member such that the movable member is movable with respect to the base member between the retracted position and the extended position, wherein the base member, the movable member, the link member, and the additional link member define a four-bar linkage.
 17. The derailleur according to claim 1, wherein the intermediate member is provided on a first side of the movable member, and the first side is opposite to a second side of the movable member and is closer to the bicycle frame than the second side in a state where the base member is attached to the bicycle frame.
 18. The derailleur according to claim 1, wherein the biasing member further has a second end portion, the intermediate member is configured to transmit the biasing force of the biasing member from the first end portion to the link member through the intermediate member, and the movable member has a guiding surface configured to contact and guide a bicycle chain, and an arrangement portion configured to arrange the second end portion and provided on the guiding surface. 